Answer
The sound level difference is $~~5.0~dB~~$ at $r = 10~m$
Work Step by Step
On the graph, we can see that the sound level difference is constant for all values of $r$
That is, the sound level difference does not depend on the value of $r$
The sound level difference is $5.0~dB$ for all values of $r$
Therefore, the sound level difference is $~~5.0~dB~~$ at $r = 10~m$
